A NEW VALIDATED METHOD FOR THE SIMULTANEOUS DETERMINATION OF A SERIES OF EIGHT BARBITURATES BY RP-HPLC Ghulam A. Shabir, 1 Tony K. Bradshaw, 1 Shafique A. Arain, 2 and Ghulam Qadir Shar 3 1 School of Life Sciences, Oxford Brookes University, Oxford, UK 2 Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow, UK 3 Sunderland Pharmacy School, University of Sunderland, Sunderland, UK & A new reversed-phase high performance liquid chromatographic (RP-HPLC) method is developed and validated for the simultaneous determination of barbitone, allobarbitone, phenobarbitone, cyclobarbitone, hexobarbitone, pentobarbitone, secobarbitone and methohexitone compounds in a single analytical run. The method uses a Phenosphere C 18 (150 mm  4.6 mm; 5 lm) column and isocratic elution. The mobile phase consisted of a mixture of methanol-water (50:50, v=v), pumped at a flow rate of 1.0 mL=min. The UV detection is set at 254 nm. The method is validated with respect to accuracy, precision (repeatability and intermediate precision), specificity, linearity, range robustness and stability of analytical solutions. All the parameters examined met the current recommendations for bioanalytical method validation. The method is specific, simple, selective and reliable for routine use in quality control analysis of barbiturates raw materials for final product release. Keywords allobarbitone, barbitone, cyclobarbitone, hexobarbitone, method develop- ment, method validation, methohexitone, pentobarbitone, phenobarbitone, reversed- phase liquid chromatography, secobarbitone INTRODUCTION Barbiturates are widely in use since the beginning of the century (barbital, 1903) especially as sedative hypnotics. With the advent of anxiolytic agents the popularity of barbiturates has suffered although they are still less costly. However, those with specialized properties such as the anticonvulsant phenobarbital continue to be commonly used. [1] In addition, abuse of barbiturates is now widespread. Due to the inter- national nature of the illegal drug market forensic laboratories encounter Correspondence: Ghulam A. Shabir, School of Life Sciences, Oxford Brookes University, Oxford OX3 0BP, UK. E-mail: gshabir@brookes.ac.uk Journal of Liquid Chromatography & Related Technologies, 33:61–71, 2010 Copyright # Taylor & Francis Group, LLC ISSN: 1082-6076 print/1520-572X online DOI: 10.1080/10826070903430175 Journal of Liquid Chromatography & Related Technologies, 33:61–71, 2010 Copyright # Taylor & Francis Group, LLC ISSN: 1082-6076 print/1520-572X online DOI: 10.1080/10826070903430175